Two adjacent implant-supported restorations in the aesthetic region: A 10-year prospective case series

INTRODUCTION

The treatment outcome of two adjacent implant-supported restorations in the maxillary aesthetic region was assessed regarding peri-implant soft and hard tissues, and satisfaction during a 10-year follow-up period.

METHODS

Twenty patients missing two adjacent teeth in the maxillary aesthetic region and treated with two implant-supported restorations were followed prospectively. The patients' clinical and radiographic parameters, as well as their satisfaction, were scored for a 10-year follow-up period.

RESULTS

Seventeen patients' data were available for the 10-year follow-up. The survival rate of the implants and restorations was 100%. The 10-year mean peri-implant bone change at the side facing the adjacent tooth was +0.11 ± 0.57 mm and at the side facing the adjacent implant was -0.08 ± 0.50 mm. The peri-implant soft tissues were healthy and the patients' satisfaction was high, but the papilla-index showed compromised inter-implant papillae and low Pink Esthetic Scores. These figures were of the same magnitude at all time points.

CONCLUSION

While it is difficult to obtain sufficient inter-implant papillae and satisfactory Pink Esthetic Scores, the initial treatment results remained stable and the patients were satisfied with the final result throughout the 10-year follow-up period.

The Success Rate of the Adhesive Partial Fixed Prosthesis after Five Years: A Systematic Review

Objective: Evaluation of the success and/or survival rates of resin-bonded fixed partial dentures (RBFPDs) reported in the scientific literature with a minimum average observation time of five years. Materials and Methods: Search conducted in Pubmed, Web of Science, and Cochrane databases in free-text format and MESH terms, until May 2021. The random-effects model was used for the estimated survival rate, percentage per year of estimated failure, and existing complications for the meta-analysis. Study heterogeneity was assessed by the inconsistency test (I2) and study quality by the Downs and Black scale. Results: Eleven articles were included, with 687 participants and 783 RBFPDs, with a mean observation time of 8.2 years, with success rates mentioned in three articles and survival rates reported in nine articles. A total of 142 failures were reported for 783 prostheses, the most frequent being debonding. The estimated failure rate was between 0.53% and 5.10% per year. The studies were of sufficient quality. In the meta-analysis, the survival rates showed a significant result (p < 0.001), with moderate heterogeneity (I2 = 58.76%). Conclusions: Within the limitations of this research, mainly related to the heterogeneity of the studies and their quality, it seems possible to conclude that RBFPDs are a viable clinical option for the rehabilitation of patients with single edentulous spaces, mainly when using a single retainer and a zirconia-ceramic prosthesis.

Customized Titanium Mesh for Guided Bone Regeneration in the Posterior Mandible in a Patient Previously Treated with Bisphosphonates

We describe the restorative treatment of an 86-year-old female patient who was referred to our specialist prosthodontics clinic. Due to secondary osteoporosis, she underwent oral antiresorptive therapy with ibandronic acid for 10 years. Although she was classified as a patient at increased risk of drug-induced osteonecrosis of the jaw, she eventually signed a consent form for fixed implant-supported prosthetic rehabilitation in her 4th sextant. However, after tooth extraction, the bone ridge was too small at the intended implant positions. Therefore, guided bone regeneration was performed with a computer-aided design/computer-aided manufacturing three-dimensional printed titanium mesh. Finally, a continuous augmented hard tissue ridge above 7 mm was found, and three implants were inserted. Eventually, after four months of submerged healing, the implants were loaded with single crowns. Now, the patient is seen regularly for supportive peri-implant therapy.

Survival Rates of Dental Implants in Autogenous and Allogeneic Bone Blocks: A Systematic Review

Background and Objectives: Preliminary studies emphasize the similar performance of autogenous bone blocks (AUBBs) and allogeneic bone blocks (ALBBs) in pre-implant surgery; however, most of these studies include limited subjects or hold a low level of evidence. The purpose of this review is to test the hypothesis of indifferent implant survival rates (ISRs) in AUBB and ALBB and determine the impact of various material-, surgery- and patient-related confounders and predictors. Materials and Methods: The national library of medicine (MEDLINE), Excerpta Medica database (EMBASE) and Cochrane Central Register of Controlled Trials (CENTRAL) were screened for studies reporting the ISRs of implants placed in AUBB and ALBB with ≥10 participants followed for ≥12 months from January 1995 to November 2021. The review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The risk of bias was assessed via several scoring tools, dependent on the study design. Means of sub-entities were presented as violin plots. Results: An electronic data search resulted in the identification of 9233 articles, of which 100 were included in the quantitative analysis. No significant difference (p = 0.54) was found between the ISR of AUBB (96.23 ± 5.27%; range: 75% to 100%; 2195 subjects, 6861 implants) and that of ALBB (97.66 ± 2.68%; range: 90.1% to 100%; 1202 subjects, 3434 implants). The ISR in AUBB was increased in blocks from intraoral as compared to extraoral donor sites (p = 0.0003), partially edentulous as compared to totally edentulous (p = 0.0002), as well as in patients younger than 45 as compared to those older (p = 0.044), cortical as compared to cortico-cancellous blocks (p = 0.005) and in delayed implantations within three months as compared to immediate implantations (p = 0.018). The ISR of ALBB was significantly increased in processed as compared to fresh-frozen ALBB (p = 0.004), but also in horizontal as compared to vertical augmentations (p = 0.009). Conclusions: The present findings widely emphasize the feasibility of achieving similar ISRs with AUBB and ALBB applied for pre-implant bone grafting. ISRs were negatively affected in sub-entities linked to more extensive augmentation procedures such as bone donor site and dentition status. The inclusion and pooling of literature with a low level of evidence, the absence of randomized controlled clinical trials (RCTs) comparing AUBB and ALBB and the limited count of comparative studies with short follow-ups increases the risk of bias and complicates data interpretation. Consequently, further long-term comparative studies are needed.

Lateral Alveolar Ridge Augmentation with an Autogenous Bone Block Graft Alone with or without Barrier Membrane Coverage: a Systematic Review and Meta-Analysis

Objectives

To test the hypothesis of no difference in implant treatment outcome following lateral alveolar ridge augmentation with autogenous bone block graft with or without barrier membrane coverage.

Material and Methods

PubMed (MEDLINE), Embase and Cochrane library search in combination with a hand-search of relevant journals was conducted. Human studies published in English until the 8^th of February 2021 were included. Randomised controlled trials with an observation period longer than three months were included. Survival of implants and suprastructures were considered as primary outcomes measures, whereas peri-implant marginal bone loss, dimensional changes of the alveolar ridge, bone regeneration, patient-reported outcome measures, biological and mechanical complications were secondary outcome measures, as evaluated by descriptive statistics and meta-analysis including 95% confidence interval (CI).

Results

Electronic search and hand-searching resulted in 411 entries. Five randomised controlled trials characterised by low or high risk of bias fulfilled inclusion criteria. No statistically significant difference between the two treatment modalities was observed in any of the outcome measures. However, barrier membrane coverage was associated with a non-significant gain in alveolar ridge width of 0.5 mm (95% CI = -0.1 to 1.1) and diminished resorption of -0.9 mm (95% CI = -2.4 to 0.7) compared with no barrier membrane coverage.

Conclusions

Comparable implant treatment outcomes were revealed following lateral alveolar ridge augmentation with autogenous bone block graft alone with or without barrier membrane coverage. However, postoperative dimensional changes of the augmented seems to be diminished with the use of barrier membrane coverage as evaluated by two-dimensional linear measurements.

Review of bone graft and implant survival rate : A comparison between autogenous bone block versus guided bone regeneration

In oral surgery, there is a multitude of bone augmentation techniques and biomaterials choices. Autogenous bone is considered the gold standard in bone graft due to its biocompatibility, osteoinduction, osteoconduction and osteogenic properties. An alternative to autogenous bone grafting is the guided bone regeneration technique. The objective of this review is to compare the results of implant survival in an autogenous bone block compared to those in a graft by guided bone regeneration. An electronic search in PubMed Central's database was performed. The search strategy was limited to human studies, full-text English or French articles published from 1996 until may 2020. All types of autogenous bone block and guided bone regeneration techniques were evaluated. In total 16 articles were included. The overall survival rate of implants was 97,9% in autogenous block (range: 95.6-100%) and 98,5% (range: 94.4-100%) in GBR. The implant survival rate does not differ between the two types of bone graft in a guided bone regeneration or in an autogenous bone block. They are comparable to the current literature data. The choice of an appropriate treatment is based on several factors related to the patient and the anatomy of the defects.

The influence of wound closure on graft stability: An in vitro comparison of different bone grafting techniques for the treatment of one-wall horizontal bone defects

OBJECTIVES

The aim of this preclinical study was to analyze and compare different grafting techniques with respect to volume stability after wound closure.

MATERIALS AND METHODS

Four different grafting techniques were evaluated in vitro for volume stability in a one-wall horizontal defect configuration. Group 1: guided bone regeneration (GBR) with collagen membrane, particulated xenograft; group 2: GBR with collagen membrane, particulated xenograft, pins; group 3: GBR with titanium-reinforced membrane, particulated xenograft, pins; group 4: autogenous block graft, particulated xenograft, collagen membrane. Cone beam computed tomography scans were performed before and after wound closure, and the horizontal bone dimensions were analyzed for stability at 0-5 mm apical to the implant shoulder (H0-H5).

RESULTS

At H0-H2, wound closure induced a statistically significant change in bone dimensions in groups 1 and 2. In group 3, only the change in H0 was significant, and for group 4, only H2 was significant.

CONCLUSION

Wound closure has a significant impact on graft stability in a one-wall horizontal defect configuration. GBR with additional membrane fixation showed better results than without. Titanium-reinforced membranes and autogenous blocks showed significantly greater volume stability than GBR with collagen membrane, especially in the coronal portion.

Effects of lateral bone augmentation procedures on peri-implant health or disease: A systematic review and meta-analysis

OBJECTIVES

This systematic review evaluated the evidence on the effect of the interventions aimed for lateral ridge augmentation (both simultaneously with implant placement or as a staged procedure) on peri-implant health or disease.

METHODS

A protocol was developed to answer the following PICO question: "In patients with horizontal alveolar ridge deficiencies (population), what is the effect of lateral bone augmentation procedures (intervention and comparison) on peri-implant health (outcome)?" Included studies were randomised controlled trials or controlled clinical trials with a follow-up of at least 12 months after implant loading. Meta-analyses were performed whenever possible, including subgroup analysis based on follow-up.

RESULTS

Twelve final publications from eight investigations were included. The results from the meta-analysis indicated that irrespective of the type of intervention, the inflammatory changes, based on bleeding on probing (%) were minimal, both at short- (n = 1; weighted mean difference [WMD] = -1.00; 95% CI [-14.04; 12.04]; p = .881) and long-term (n = 5; WMD = -5.63; 95% CI [-18.42; 7.16]; p = .881). When comparing different treatment modalities, no significant differences were observed (n = 6; WMD = -3.36; 95% CI [-12.49; 5.77]; p < .471). Similarly, changes in probing pocket depth and marginal bone levels were not significantly different among groups. The incidence of peri-implantitis was evaluated in three investigations and varied from 16% to 26% after a follow-up period of 6-8 years.

CONCLUSIONS

The results from this systematic review and meta-analysis have shown that lateral ridge augmentation procedures can maintain peri-implant health over time with low mucosal inflammatory changes and a relatively small incidence of peri-implant bone loss.

The effect of resorbable membranes on one-stage ridge augmentation in anterior single-tooth replacement: A randomized, controlled clinical trial

AIM

To evaluate the effect of resorbable membranes on one-stage ridge augmentation procedures in small (2-4 mm) buccal bony dehiscences in anterior maxillary single-tooth replacement.

MATERIALS AND METHODS

Patients with a buccal bony dehiscence after implant placement in the esthetic zone were randomly allocated to one-stage ridge augmentation with (M+) or without a membrane (M-). Second-phase surgery was performed after 8 weeks, and follow-up was performed 1, 6, and ≥12 months after loading. Outcomes included implant survival and success, complications, clinical and radiographic parameters, esthetic results and patient satisfaction.

RESULTS

Fifty-two patients were randomized to one-stage ridge augmentation with (n = 25) or without use of a membrane (n = 27). No significant differences in implant survival and success have been observed. The risk of having a small mucosal dehiscence was more than six times higher in the M+ group than in the M- group (RR 6.24, 95% CI 0.81 to 48.21). At the last follow-up, the bleeding index (BI) was marginally higher in the M+ group (14/9/2/0) compared to the M- group (24/2/0/0) (U = 205, Z = -2.97, p = .003, r = .42). The median change in marginal bone level was statistically lower in the M+ group (0.06 mm) than the M- group (0.60 mm) at last follow-up (U = 120, Z = -2.73 a p = .006 r = .42). Total pink esthetic index (PES) and white esthetic score (WES) and combined PES/WES were not significantly different between treatment groups at more than 12 months after loading. Only the subcategory root convexity/soft tissue color scored significantly lower in the M+ group (1.5) compared to the M- group (2.0) at the last follow-up (U = 172, Z = -2.34, p = .019 r = .34). No differences were found in patient satisfaction.

CONCLUSION

The use of a resorbable membrane in small buccal bony dehiscences in anterior maxillary single-tooth replacement resulted in less marginal bone loss, but showed more mucosal dehiscences, higher bleeding scores and lower scores on root convexity and soft tissue color after at least one year of loading. No effect was seen on implant survival and success, overall esthetic results, and patient satisfaction. The research protocol was registered at the Dutch Trial Register (NTR) with ID NTR6137.

Cortical Bone Augmentation Versus Nerve Lateralization for Treatment of Atrophic Posterior Mandible: A Retrospective Study and Review of Literature

PURPOSE

We sought to assess implant success/survival/failure rate following cortical autogenous tenting technique (CATT) versus inferior alveolar nerve transposition (IANT) in the posterior mandible.

MATERIALS AND METHODS

Patients who underwent these two procedures between 2007 and 2011 were analyzed. CATT was performed using lateral ramus block graft and implants were inserted simultaneously or after 4 to 6 months. In IANT, implants were placed simultaneously after nerve transposition with or without mental foramen involvement. Data regarding marginal bone level (MBL), pus discharge (PD), neurosensory dysfunction (NSD), implant mobility, and failure were collected. Success rate was measured based on Pisa Consensus. Independent sample t-test with a significance level of 0.05 was used to compare implant dimensions and MBL changes between the two techniques.

RESULTS

A total of 118 patients with a mean age of 54.85 years were included. The mean follow-up after CATT and IANT was 37.97 and 18.51 months, respectively. The overall survival and success rates of dental implants in the CATT group were 98.73% and 71.52%, respectively. The corresponding values for IANT subjects were 98.74% and 94.56%, respectively. Implant length and diameter in IANT group were significantly longer and wider than implants used after CATT (p value < .001). MBL changes in both techniques were less than 1 mm (p value = .79). Two cases of NSD, seven PD, and two implant failures were found in the CATT group. For IANT patients, seven permanent NSD, two PD, two implant failures, and one mandibular fracture were documented.

CONCLUSION

Both techniques had implant survival rates similar to implants placed in unaltered bone. A higher implant success rate, albeit with higher incidence of long-lasting nerve damage, was observed in the IANT group.

Strategies for alveolar ridge reconstruction and preservation for implant therapy

PURPOSE

In dental implant treatment, ridge preservation and immediate or early implant placement are recommended to minimize bone resorption after tooth extraction and achieve esthetic outcomes. However, there is no consensus concerning the efficacy of this surgical method. There is also no consensus on the efficacy of bone and soft tissue grafts and surgical methods for alveolar ridge reconstruction.

STUDY SELECTION

This paper reports ridge alteration in the anterior maxilla after tooth extraction, and summarizes the efficacy of various ridge preservation methods and immediate or early implant placement as alveolar ridge preservation methods to minimize bone resorption after tooth extraction. The advantages and complications of alveolar ridge reconstruction methods, and the efficacy and surgical method of soft tissue graft are reviewed.

RESULTS

The anterior maxilla is in the esthetic zone, and the thickness of the bone on the labial side around the natural tooth is less than 1mm in many cases. Therefore, it is impossible to prevent bone resorption completely, even if ridge preservation and immediate or early implant placement are performed after tooth extraction. It is necessary to obtain stable and long-term esthetics by combining connective tissue and free gingival grafts, in addition to hard tissue augmentation.

CONCLUSIONS

It is important to consider the burden and level of satisfaction of patients, such as in terms of donor site morbidity in hard and soft tissue grafting, and to pay attention to appropriate indications to avoid overtreatment.

The outcome of intraoral onlay block bone grafts on alveolar ridge augmentations: a systematic review

Aim: The purpose of this study was to systematically review clinical studies examining the survival and success rates of implants placed with intraoral onlay autogenous bone grafts to answer the following question: do ridge augmentations procedures with intraoral onlay block bone grafts in conjunction with or prior to implant placement influence implant outcome when compared with a control group (guided bone regeneration, alveolar distraction, native bone or short dental implants.)? Material and Method: An electronic data banks and hand searching were used to find relevant articles on vertical and lateral augmentation procedures performed with intraoral onlay block bone grafts for dental implant therapy published up to October 2013. Publications in English, on human subjects, with a controlled study design –involving at least one group with defects treated with intraoral onlay block bone grafts, more than five patients and a minimum follow-up of 12 months after prosthetic loading were included. Two reviewers extracted the data. Results: A total of 6 studies met the inclusion criteria: 4 studies on horizontal augmentation and 2 studies on vertical augmentation. Intraoperative complications were not reported. Most common postsurgical complications included mainly mucosal dehiscences (4 studies), bone graft or membrane exposures (3 studies), complete failures of block grafts (2 studies) and neurosensory alterations (4 studies). For lateral augmentation procedures, implant survival rates ranged from 96.9% to 100%, while for vertical augmentation they ranged from 89.5% to 100%. None article studied the soft tissues healing. Conclusions: Survival and success rates of implants placed in horizontally and vertically resorbed edentulous ridges reconstructed with block bone grafts are similar to those of implants placed in native bone, in distracted sites or with guided bone regeneration. More surgical challenges and morbidity arise from vertical augmentations, thus short implants may be a feasible option.

Key words:Alveolar ridge augmentation, intraoral bone grafts, onlay grafts, block grafts, dental implants.

Horizontal augmentation of thin maxillary ridge with bovine particulate xenograft is stable during 500 days of follow-up: preliminary results of 12 consecutive patients

PURPOSE

The purpose of our evaluation was to determine the stability of the horizontal augmentation of the anterior maxilla using particulate bovine xenograft under a membrane. The hypothesis to be tested was that bovine particulate graft material is effective for augmenting the narrow ridge of the anterior maxilla and can maintain its augmentation dimension within 1 mm over time.

MATERIALS AND METHODS

A consecutive series of 12 patients who received a bovine particulate graft were evaluated in a retrospective manner. Using a standardized method, their cone beam scans were measured for width at 3 vertical locations preoperatively (T0), immediately after the augmentation (T1), 3 to 6 months after augmentation and before implant placement (T2), immediately after implant placement (T3), and at the longest postoperative point (T4). One examiner, who was not involved in the surgical procedures, measured all the radiographs. The intraexaminer error approximated 0.2 mm in all areas of measurements. A linear mixed effects model was used to determine the stability of the augmentation over time.

RESULTS

The most coronal aspect of the crest had the least width augmentation. The midway region and apical region had the greatest width changes (P < .001). Within the sample size, there were no statistically significant differences in width changes over time after augmentation was performed.

CONCLUSIONS

Within the limitations of this sample, horizontal ridge augmentation using bovine particulate material under a membrane was stable over time in the anterior maxilla.

Performance of the Straumann Bone Level Implant system for anterior single-tooth replacements in augmented and nonaugmented sites: a prospective cohort study with 60 consecutive patients

AIM

The purpose of this prospective study was to evaluate radiographic, clinical and aesthetic outcomes and patient satisfaction of cases treated with platform-switched single implant restorations in the aesthetic region of the maxilla. Furthermore, the influence of an augmentation procedure 3 months before implant placement and the type of restoration (screw-retained vs. cement-retained) was evaluated.

MATERIAL AND METHODS

Sixty patients with a missing anterior tooth in the maxilla were treated with a Straumann Bone Level Implant. Bone augmentation was performed in 29 patients at 3 months before implant placement. Implants were loaded after 3 months of submerged healing. Follow-up was conducted at 7 and 18 months after implant placement. Peri-implant mucosa and implant crown aesthetic outcomes were determined using the Implant Crown Aesthetic Index (ICAI) and the Pink Esthetic Score-White Esthetic Score (PES-WES).

RESULTS

No implants were lost. At 18 months after implant placement, mean bone level change was -0.10 ± 0.27 mm and mean probing pocket depth was 2.57 mm. No differences were found between augmented and nonaugmented sites (P = 0.28). The ICAI indicated satisfactory mucosa and crown aesthetics in 67% and 75% of the cases, respectively, while the PES score was 14.4. ICAI mucosa (P = 0.004) and PES (P = 0.02) scores were significantly less favourable for augmented sites compared with nonaugmented sites. Patient satisfaction was high (8.9 ± 1.1 on VAS-score).

CONCLUSIONS

From the present prospective, clinical study, it can be concluded that the Straumann Bone Level Implant shows an excellent survival rate, marginal bone stability and good clinical and aesthetic results. Bone augmentation before implant placement does not lead to more marginal bone loss. However, less favourable pink aesthetic outcomes were found in augmented sites compared with nonaugmented sites, while no differences were found between cement-retained and screw-retained restorations.

Clinical, aesthetic, and patient-related outcome of immediately loaded single implants in the anterior maxilla: a prospective study in extraction sockets, healed ridges, and grafted sites

PURPOSE

The objective of this prospective clinical study was to document the overall treatment outcome of immediately loaded single Astra Tech Osseospeed™ (Astra Tech AB, Mölndal, Sweden) implants placed in extraction sockets, healed ridges, and grafted sites.

MATERIALS AND METHODS

Forty-eight patients in need of a single implant in the anterior maxilla (15-25) were recruited. Patients were allocated to a conventional implant treatment (CIT) or immediate implant treatment (IIT) group on the basis of specific criteria. If the buccal bone plate was damaged or missing upon tooth removal, patients were allocated to a grafted implant treatment (GIT) group. Irrespective of the treatment concept, implants were immediately provisionalized. Hard and soft tissue alterations, aesthetic parameters (pink and white esthetic scores, [PES and WES]) and patient's opinion (Oral Health Impact Profile [OHIP-14] questionnaires) were registered at different time points.

RESULTS

After 1 year of function, the overall implant survival rate was 98% with one failure following IIT. The mean bone level to the implant-abutment interface was 0.65 (SD 0.79), 0.85 (SD 0.64), and 0.56 mm (SD 0.44) for CIT, IIT, and GIT. Complete papilla loss was rare following either strategy. Mean midfacial recession amounted to 1.00 (SD 1.15), 0.12 (SD 0.78), and 0.49 mm (SD 0.82) for CIT, IIT, and GIT, respectively. The aesthetic outcome showed a mean PES of 10.30 (SD 1.89) and mean WES of 7.11 (SD 2.14), all patients considered. Patient's satisfaction showed a significant improvement after 1 year of function on all seven domains (p < .001).

CONCLUSIONS

This prospective study showed that single implants clinically and aesthetically perform well under immediate non-occlusal loading conditions in the premaxilla. In this context, it is of pivotal importance to stress that patients were carefully selected for IIT and GIT.

Timing of implant placement and augmentation with bone replacement material: clinical assessment at 8 and 16 months

PURPOSE

The purpose of this study is to evaluate implants placed at different times of bone augmentation.

MATERIALS AND METHODS

Four implants were placed in seven dogs: one at a 6-month bovine mineral grafted site (6-month Bio-Oss® grafted site [6mBio]), one at a grafted membrane-protected simultaneously augmented (Fresh Bio-Oss® grafted site [FrBio]) site, one at a clotted (nongrafted clotted membrane-protected site [Clot]) membrane-protected site, and one at a pristine (nongrafted uncovered site [Cont]) site. Implants were exposed after 6 months. The same protocol was repeated on the contralateral side, at a delay of 8 months. Peri-implant care was performed throughout the hygienic phase (2 and 10 months, respectively) every 48 to 72 hours. Probing depth and bleeding on probing were recorded. Implant stability was determined by a Periotest® (Medizintechnik Gulden, Modautal, Germany). Statistical analysis was conducted using analysis of variance with repeated measures.

RESULTS

Average probing depth at the simultaneously grafted sites was 2.21 mm and 2.03 mm at 8 and 16 months, respectively. At the 6-month grafted sites, it was 1.96 mm and 1.57 mm. At the Clot sites, it was 2.68 mm and 2.07 mm, and 2.21 mm and 1.82 mm at the Cont sites, respectively. The average bleeding on probing was 0.50 and 0.42 at the FrBio sites, and 0.35 and 0.07 at the 6mBio sites during the respective periods. At the Clot sites, it was 0.50 and 0.28, and at the Cont sites, 0.43 and 0.21, respectively. Probing depth significantly reduced over the time at 6mBio, Clot, and Cont sites (p < .03). Average implant stability score at the FrBio sites was -0.24 and -0.27, and -0.50 and -0.46 at the 6mBio sites, at 8 and 16 months, respectively. At the Clot sites, it was -0.35 and -0.46. Cont sites averaged -0.37 at both periods. Implant stability was significantly higher (p < .005) comparing 6mBio over FrBio, 6mBio over Cont, and Clot over FrBio sites.

CONCLUSIONS

Immediate and delayed augmentations are safe modes. Probing depth and bleeding indices gradually improved along time. Implant stability was higher at the delayed mode.

Long-term rabbits bone response to titanium implants in the presence of inorganic bovine-derived graft

This study evaluated bone responses to titanium implants in the presence of an inorganic graft material. The bilateral mandible incisors of 24 rabbits were surgically extracted and one of the exposed sockets, chosen at random, was filled with an inorganic xenogenic bone graft (Gen-ox®), whereas the remaining socket was left to heal naturally and served as a control. After 60 days, titanium implants were inserted in the specific areas, and on days 0, 30, 60, and 180 after the implant insertions, six animals of each group were killed. Digital periapical radiography of implant region was obtained and vertical bone height (VBH) and bone density (BD) were evaluated by digital analysis system. In the undecalcified tissue cuts, bone-to-implant contact (BIC) and bone area (BA) within the limits of the implant threads were evaluated and compared statistically by means of two-way ANOVA and Tukey's test (ρ < 0.05). No significant differences were detected in VBH and BA, either between groups or between different experimental intervals. The BD was significantly higher in the experimental group than in the control group in all the intervals tested, but there were no significant differences by interval. The BIC was statistically lower in the control group on day 0; however, a significant increase was observed on days 60 and 180 (ρ < 0.05). The use of an inorganic xenograft prior to insertion of a titanium implant did not interfere with the course of osseointegration.

Simultaneous versus two-stage implant placement and guided bone regeneration in the canine: histomorphometry at 8 and 16 months

AIM

To compare the effect of timing of implant placement and guided bone regeneration (GBR) procedure on osseointegration and newly formed bone at 8 and 16 months.

MATERIAL AND METHODS

In seven dogs, four different sites were bilaterally established: (1) an implant placed in a 6-month healed (6m-GBR) bovine bone mineral (BBM) grafted site; (2) a simultaneously placed implant with the grafted BBM (Si-GBR) followed by a membrane coverage; (3) an implant placed in a membrane-protected non-grafted defect; and (4) an implant placement in a naturally healed site (Cont). Histomorphometry was obtained at 8 and 16 months post-implant placement. Bone-implant contact (BIC), crestal bone resorption (CBR), vertical intra-bony (VIB) defect, bone (BAF) and particle (PAF) area fractions, and osteoconductivity (CON) levels were measured.

RESULTS

In all sites, BIC ranged between 62% and 79% with no significant differences. PAF ranged from 17% to 27%, with no effect of time. At 8 and 16 months, BAF was significantly smaller at the Si-GBR site when compared with all other sites, CON was significantly greater at the 6m-GBR site, and CBR and VIB were significantly smaller at the 6m-GBR when compared with the Si-GBR sites.

CONCLUSIONS

The simultaneous and delayed techniques both showed a similar osseointegration level over time. However, the staged approach showed enhanced newly formed bone, higher osteoconduction around the grafted mineral, less CBR, and smaller vertical bone defect over time compared with the combined approach.

Interventions for replacing missing teeth: horizontal and vertical bone augmentation techniques for dental implant treatment

BACKGROUND

Dental implants require sufficient bone to be adequately stabilised. For some patients implant treatment would not be an option without horizontal or vertical bone augmentation. A variety of materials and surgical techniques are available for bone augmentation.

OBJECTIVES

To test whether and when augmentation procedures are necessary and which is the most effective technique for horizontal and vertical bone augmentation.

SEARCH STRATEGY

The Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE and EMBASE were searched. Several dental journals were handsearched. The bibliographies of review articles were checked, and personal references were searched. More than 55 implant manufacturing companies were also contacted. Last electronic search was conducted on 11 June 2009.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of different techniques and materials for augmenting bone horizontally or vertically or both for implant treatment reporting the outcome of implant therapy at least to abutment connection. Trials were divided into two broad categories: horizontal augmentation and vertical augmentation techniques.

DATA COLLECTION AND ANALYSIS

Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted independently and in duplicate. Authors were contacted for any missing information. Results were expressed as random-effects models using mean differences for continuous outcomes and odd ratios for dichotomous outcomes with 95% confidence intervals. The statistical unit of the analysis was the patient.

MAIN RESULTS

Thirteen RCTs out of 18 potentially eligible trials were suitable for inclusion. Three RCTs (106 patients) dealt with horizontal and 10 trials (218 patients) with vertical augmentation. Since different techniques were evaluated in different trials, only one meta-analysis could be performed. When comparing whether vertical augmentation procedures are advantageous over short implants, a meta-analysis of two trials resulted in more implant failures odds ratio (OR) = 5.74 (95% confidence interval (CI) 0.92 to 35.82; borderline significance, P = 0.06) and statistically more complications OR = 4.97 (95% CI 1.10 to 22.40) in the vertically augmented group. When comparing various horizontal augmentation techniques (three trials) no statistically significant differences were observed. When comparing various vertical bone augmentation techniques (eight trials) no statistically significant differences were observed with the exception of three trials which showed that more vertical bone gain could be obtained with osteodistraction than with inlay autogenous grafts (mean difference 3.25 mm; 95% CI 1.66 to 4.84), and with a bone substitute rather than autogenous bone in guided bone regeneration (mean difference 0.60 mm; 95% CI 0.21 to 0.99) in posterior atrophic mandibles, and that patients preferred a bone substitute block than a block of autogenous bone taken from the iliac crest (OR = 0.03; 95% CI 0.00 to 0.64; P = 0.02).

AUTHORS' CONCLUSIONS

These conclusions are based on few trials including few patients, sometimes having short follow-up, and often being judged to be at high risk of bias. Various techniques can augment bone horizontally and vertically, but it is unclear which are the most efficient. Short implants appear to be a better alternative to vertical bone grafting of resorbed mandibles. Complications, especially for vertical augmentation, are common. Some bone substitutes could be a preferable alternative to autogenous bone. Osteodistraction osteogenesis allows for more vertical bone augmentation than other techniques which on the other hand can allow for horizontal augmentation at the same time. Titanium screws may be preferable to resorbable screws to fixate onlay bone grafts.

The Influence of Barrier Membranes on Autologous Bone Grafts

In implant dentistry, there is continuing debate regarding whether a barrier membrane should be applied to cover autologous bone grafts in jaw augmentation. A membrane would prevent graft remodeling with resorption and enhance graft incorporation. We hypothesized that membrane coverage does not effect resorption and incorporation of autologous onlay bone grafts. We treated 192 male Sprague-Dawley rats. A 4.0-mm-diameter bone graft was harvested from the right mandibular angle and transplanted to the left. Poly(DL-lactide-ε-caprolactone), collagen, and expanded polytetrafluoroethylene membranes were used to cover the grafts. The controls were left uncovered. Graft resorption at 2, 4, and 12 weeks was evaluated by post mortem microradiography and microCT. Analysis of the data showed no significant differences among the 4 groups. This demonstrates that the indication of barrier membrane use, to prevent bone remodeling with resorption and to enhance incorporation of autologous onlay bone grafts, is at least disputable.